This application in general relates to an improved valving system for dividing water flow to a turbine engine.
Some turbine engines require water to be injected into the combustion chamber at a plurality of points for emission control. Complicated valving systems have been utilized in the prior art to evenly distribute and supply the water to these plural points. As many as fourteen water supply lines need to be supplied with relatively equal amounts of water. A turbine engine could be described as turbine blade mounted in a combustion chamber such that combustion drives the blade. One such turbine is used as an electric generator.
Prior art valve systems which divide flow between the various water supply lines exist. Those systems typically utilize a plurality of valves, and do not always equally distribute and adequately supply the water to the various supply lines.
One prior art valve operates to divide a water supply into fourteen relatively equal flows. Fourteen separate water flows are initially blocked by a single staging valve which is closed upon start-up of the engine. The water being blocked by the staging valve passes through restrictions leading to an isolation valve. The isolation valve is selectively opened or closed to allow flow to the turbine engine. Upon start-up of the engine the isolation valve is opened and water is delivered to the combustion chamber. After start-up, the staging valve is opened to increase the flow of water through the isolation valves into the engine.
This known staging valve includes a spool valve which has a valving land and groove at a central location. The water being delivered to the turbine engine either moves through the valving groove or is blocked by the valving land. Separate pistons abut the ends of the spool valve, and hydraulic chambers are defined outwardly of the pistons. The hydraulic chambers are selectively supplied with pressurized oil to move the pistons and change the position of the spool valve. If the high pressure oil leaks past the valving land, oil could be mixed with the water delivered to the combustion chamber of the turbine engine. This is undesirable and can increase emissions from the turbine engine. Reduction of emissions is a major goal in engine design. Also, water may leak from the valving groove towards the hydraulic chambers. If this water reaches the hydraulic chambers it could degrade the oil.
Since this known spool valve is positioned by separate hydraulically actuated pistons, there are leakage spaces between the pistons and the spool valve. Further, a complicated drain system is utilized to prevent mixing of the oil and water. In part, the drain system incorporates the spaces between the pistons and the spool valve. It is desirable to develop a simpler, more effective sealing and drain system for the spool valve.